Thank you mollusque! In my line of work where we get more than a few European names, it's really helpful to be able to label these special letters and symbols. (As in, "Don't forget to put the bolle in Håkan Hardenberger and the hacek in Dvořák.") Those two had been bothering me.

Biscuit was supposed to be a hint. I had a vague memory that the word meant "biscuit", but couldn't recall it. But I finally found it here--the ring over the A in Å is a bolle, which means "bowl" or "bun" in Swedish.

The same site says the slash through the o in ø is a streg, which means "line" in Danish.